destructive

Synonyms: annihilative baleful baneful calamitous cancerous cataclysmic catastrophic consumptive cutthroat damaging deadly deleterious detrimental dire disastrous eradicative evil extirpative fatal fell harmful hurtful internecine lethal lethiferous mortal noisome noxious pernicious pestiferous pestilential ruinous slaughterous suicidal toxic venomous wrackful wreckful

Antonyms: aiding assisting building creative helpful productive

Synonyms: abrasive adverse antagonistic cankerous caustic contrary corrosive deleterious derogatory detrimental discouraging discrediting erosive hostile injurious invalidating negative offensive opposed troublesome undermining vicious

Antonyms: encouraging hopeful positive